Conventional motor vehicles have a front end assembly comprised of a pair of laterally spaced fenders having their forward ends connected by a transversely extending header assembly including a radiator support and a header panel. The fenders and the header panel define an engine compartment opening which is selectively opened and closed by a hood mounted on the fenders by a pair of hinges having a hood link attached to the hood and a fender link attached to the fender. A striker is mounted at the forward end of the hood and cooperates with a latch mounted on the header assembly to latch the hood in the closed position. Adjustable screws are conventionally mounted on the header assembly adjacent the corners of the hood to engage and support the forward undersurface of the hood.
It is well known in the aforedescribed front end structure to make the connection between the various component parts by the use of bolts which extend through elongated holes so that the parts can be adjusted relative one another by loosening and then tightening the bolts. It is also well known to employ assembly fixtures during assembly of the fenders and header assembly to the body to position the parts relative one another prior to the tightening of the bolts to the specified torque so that the front end structure provides a square hood opening and a uniform gap between the rear edges of the fenders and the forward edges of the vehicle doors.
It is also desirable for the adjacent appearance surfaces to be aligned in the vertical direction as well as to achieve a uniform spacing of the hood from the fenders and header assembly. The hood hinges are conventionally provided with slotted holes so that the vertical, transverse, and longitudinal location of the hood can be adjusted relative the fenders and header assembly to precisely align the outer appearance surfaces of the hood relative the fenders and header assembly and to center the hood within the hood opening. This alignment and centering of the hood is obtained through alternating steps of adjustment and inspection. More specifically, it is common practice for the assembly worker to employ his skill and experience in estimating an initial attachment of the hood hinges to the hood and the fender and the appropriate adjustment of the adjusting screws. The hood is then closed to observe any disparity in the alignment and centering of the hood relative the fenders and the header panel. The hood hinge bolts are then loosened or the adjusting screws are adjusted to bring the hood to a better fit with the fenders and header assembly. This procedure of alternating inspection and adjustment is repeated until an acceptable hood fit is obtained.
The assembly worker's attempt at precise alignment of the hood in a minimum of trial fittings is frustrated by the variation in the size, alignment, centering, and conformance to shape which result from the application of conventional manufacturing and assembly techniques. For example, it is known that stamped steel parts will vary somewhat in dimension and shape because of spring-back of the pressed steel. Furthermore, the welded assembly of two sheet steel parts, for example, the inner and outer hood panels, can result in a variation in the dimensions of the finished parts.